A big problem for controlling access to portions of the World Wide Web is that the number of web addresses is gigantic, and the ownership and content of addresses change over time.
Previous approaches for web access control make use of manually composed white and blacklists, which may be collaboratively maintained by many users. White and blacklists rely on human manual input for updates, and are binary in nature. If the lists are about sites with violent content, for instance, they contain no information about any other kind of site. If a manager wishes to block employees from visiting news sites during working hours, if there is no such list of sites, then it cannot be done. This means the manager, parent, or other person trying to control interne access has to tailor their requirements to the lists available, rather than the other way around.
The embodiments described below are not limited to implementations which solve any or all of the disadvantages of known web site access control systems.